Cloned genes for the 70,000 dalton heat shock protein and actin from Drosophila melanogaster have been transcribed in vitro employing extracts from HeLa cells and Drospophila Kc cells. Preliminary mapping of the transcription start sites has been accomplishing by using templates shortened to varying extents by restriction endonucleases. The proposed research program will focus on several aspects of the in vitro transcription of these genes. These include (1) Definition of the sites of initiation of transcription observed using the homologous Kc cell extract and the heterologous HeLa extract from the 70K HSP and actin genes. (2) Determination of the DNA sequences involved in regulation of transcription initiation, heat shock control and termination. (3) Characterization of the protein components involved in the induction of the heat shock response. (4) Analysis of the extent the HeLa and Kc cell extracts resemble each other in transcription of the 70K HSP and actin genes. These studies will considerably expand the knowledge of transcriptional control mechansims in this well defined eucaryotic system.